Wang Shujian, Wu Chunzheng, Yu Hongbo, Li Tong, Yan Xuedong, Yan Bo, Yin Hongfeng
Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences , 1219 Zhongguan West Road , Ningbo , Zhejiang 315201 , P. R. China.
Ningbo Polytechnic , 388 East Lushan Road , Ningbo , Zhejiang 315800 , P. R. China.
ACS Appl Mater Interfaces. 2020 Feb 26;12(8):9966-9976. doi: 10.1021/acsami.9b21077. Epub 2020 Feb 13.
Nanosized Ir catalysts suffer from serious side reactions and poor stability during hydrogenation of substituted nitroaromatics to produce aromatic amines. In this work, core-shell nanostructures with sub-4 nm Ir-CoO hybrid cores and mesoporous SiO shells were designed and prepared to overcome these problems. The Ir-CoO hybrid cores were converted from IrCo alloy nanoparticles (NPs) inside SiO through in situ calcination and reduction pretreatments. The SiO mesoporous shells in Ir-CoO@SiO nanoreactors prevented the agglomeration/sintering of IrCo NPs, while allowing the free reactants and products (big molecules). The synergy between Ir and CoO species improved H adsorption, thus affecting the reaction rate as well as the selectivity to aromatic amines. As a result, the obtained Ir-CoO@SiO nanocatalyst showed tremendous improvement in catalytic activity, selectivity, and stability.
纳米级铱催化剂在将取代硝基芳烃加氢制备芳胺的过程中存在严重的副反应和较差的稳定性。在这项工作中，设计并制备了具有小于4纳米的铱-氧化钴混合核和介孔二氧化硅壳的核壳纳米结构，以克服这些问题。铱-氧化钴混合核是通过对二氧化硅内部的铱钴合金纳米颗粒进行原位煅烧和还原预处理而转化得到的。铱-氧化钴@二氧化硅纳米反应器中的二氧化硅介孔壳防止了铱钴纳米颗粒的团聚/烧结，同时允许自由反应物和产物（大分子）通过。铱和氧化钴物种之间的协同作用改善了氢吸附，从而影响了反应速率以及对芳胺的选择性。结果，所获得的铱-氧化钴@二氧化硅纳米催化剂在催化活性、选择性和稳定性方面有了巨大的提高。
